Radio Frequency Signal Router

ABSTRACT

A RF router for routing n input signals to m destinations, where the router comprises a backplane coupled to a plurality of RF input terminals, a plurality of RF output terminals, a plurality of splitters and a plurality of connectors. The backplane is also coupled to a controller and a plurality of connectors for receiving a plurality of switching matrices. The RF router comprises a plurality of u×v input switch matrices, a plurality of p×q intermediate switch matrices and a plurality of r×s output switch matrices, where at least one of the plurality of u×v input switch matrices, the plurality of p×q intermediate switch matrices and the plurality of r×s output switch matrices are redundant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/447,817, filed on Apr. 16, 2012. The entire contents of U.S. patentapplication Ser. No. 13/447,817 are hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates to routers for radio frequency signals.

BACKGROUND OF THE INVENTION

Radio frequency (RF) signals are commonly switched between source anddestination devices using patch panels. In a static system, patch panelsmay be simple and inexpensive to use. However, patch panels may not bewell equipped to manage dynamic systems, such as, for example, thosesystems where signal routes are frequently changed. Patch panels mayalso be undesirable when RF signals are switched between a large numberof sources and destinations. This may be because switching between alarge number of sources and destinations may require a large number ofcables that may have to be manually patched, making the experience verylabour intensive.

Conventional RF routers (or RF routing switchers) route RF signalsbetween source and destination using solid state switches. The purposeof an n×m RF router is to allow the user to connect RF signals from upto “n” source devices to as many as “m” destination devices. Somedevices may be both source and destination devices and may be coupled toeither one or more inputs of a RF router and to one or more outputs ofthe RF router. The variable “n” refers to the number of RF input signalsthe router can accommodate and “m” refers to the number of outputs therouter supports. The number of inputs and outputs that a RF router canhandle is often referred to as the size, format or dimension of arouter. For example, a router capable of routing 64 inputs to 32 outputshas a size or format of 64×32.

Through a controller (which may be integrated with the router or may beexternally coupled to the router), an n×m RF router can be configured todirect any of its n inputs to be routed to any combination of its moutputs. This enables the user to connect RF source devices to therouter's inputs, and RF destination devices to the router's outputs, andmake and break connections without having to rewire the circuit everytime that a new configuration is desired.

RF signals are used to transmit increasingly complex data signals. Forexample, digital audio/video signals for high definition televisioncontain significantly more information than older forms of RF signalssuch as AM radio. In addition, many more signals must be processed inmodern signal processing systems. In some regions, hundreds of signalsare available for viewing or listening. Due to the prevalence of the useof RF signals to transmit data, and the corresponding increase incomplexity in RF signal networks, there is a need for large format n×mRF routers.

As the RF router dimensions increase, several undesirable featuresresult. RF routers with high numbers of inputs and outputs typically arephysically very large, due to the common practice of using activecomponents to divide incoming signals. Large number of active componentsoccupies a substantial space on a circuit board. The use of a largenumber of active components also increases the amount of energy consumedby a typical router, and simultaneously increases the likelihood ofmalfunction.

SUMMARY

In a first aspect, some embodiments of the invention provide a RF routerfor routing n input signals to m destinations, where the routercomprises a backplane coupled to a plurality of RF input terminals, aplurality of RF output terminals, a plurality of splitters and aplurality of connectors. The backplane is also coupled to a controllerand a plurality of connectors for receiving a plurality of switchingmatrices. The RF router comprises a plurality of u×v input switchmatrices, a plurality of p×q intermediate switch matrices and aplurality of r×s output switch matrices, where at least one of theplurality of u×v input switch matrices, the plurality of p×qintermediate switch matrices and the plurality of r×s output switchmatrices are redundant. In this example, the plurality of splitters andthe plurality of combiners, and the backplane providing electricalinterconnections between the plurality of switch matrices, connectors,splitters, and RF input and output terminals are passive.

In some cases, the RF router comprises a tone injecting module forinjecting tones into incoming RF signals when the signal arrives at someor all of the u×v input switch matrices. The RF router also comprises atone monitoring module for monitoring the tones when the signals arriveat some or all of the u×v input switch matrices, p×q intermediate switchmatrices and r×s output switch matrices.

In various cases, the backplane of the RF router comprisesself-terminating connectors that are configured to close two or morepins of the connector in the absence of any switch matrices or cardscomprising the switch matrices.

The RF router may further comprise sensors in the switching matrices todetect their removal from the connectors coupled to the backplane. Thesensors may be capacitive sensors. The switching matrices may comprisemodule ejectors and the sensors may be configured to detect proximity ofapproaching objects or actual contact by the objects to detect anupcoming or actual removal of the switching matrices from theconnectors.

In various cases, the backplane of the RF router is configured such thatthe lengths of each of the traces from splitters to u×v input switchmatrices are equal. Similarly, the lengths of each of the traces fromu×v input switch matrices to p×q intermediate switch matrices are equal.The backplane further comprises equal traces from the p×q intermediateswitch matrices to r×s output switch matrices and from r×s output switchmatrices to combiners.

In another broad aspect, there is provided a RF router comprising: acontroller; an input stage comprising a plurality of RF input terminalsconfigured to receive input RF signals, a plurality of u×v input switchmatrices, and a splitter connected to each RF input terminal forcoupling a corresponding input RF signal to at least one u×v inputswitch matrix; a plurality of p×q intermediate switch matrices, whereinputs of each p×q intermediate switch matrices are coupled to outputsof the u×v input switch matrices such that each input of each p×qintermediate switch matrix is coupled to exactly one output of theplurality of u×v input switch matrices; an output stage comprising: aplurality of r×s output switch matrices, wherein inputs of each r×soutput switch matrix are coupled to outputs of the p×q intermediateswitch matrices such that each input of each r×s output switch matrix iscoupled to exactly one output of the plurality of p×q intermediateswitch matrices; and a combiner coupled between the plurality of r×soutput switch matrices and a plurality of RF output terminals, whereineach RF output terminal is configured to provide an output RF signal;and wherein at least one of the plurality of u×v input switch matrices,the plurality of p×q intermediate switch matrices and the plurality ofr×s output switch matrices are redundant.

In some cases, the inputs of each p×q intermediate switch matrix arecoupled to different u×v input switch matrices.

In some other cases, the inputs of each r×s output switch matrix arecoupled to different p×q intermediate switch matrices.

The splitters of the RF router may be configured to couple thecorresponding input RF signal to different u×v input switch matrices.

The combiners of the RF router may be configured to couple different r×soutput switch matrices to a RF output terminal.

In some cases, the RF router of claim 1, wherein the RF router has atleast 64 RF input terminals. In some other cases, the RF router has atleast 64 RF output terminals.

In some cases, wherein when the RF router has 64 RF input terminals and64 RF output terminals, the RF router comprises 16 u×v input switchmatrices, 16 p×q intermediate switch matrices and 16 r×s output switchmatrices, wherein the plurality of u×v input switch matrices, theplurality of p×q intermediate switch matrices and the plurality of r×soutput switch matrices are 8×8 switch matrices.

In some cases, wherein when the RF router has 64 RF input terminal and128 RF output terminals, the RF router comprises 16 u×v input switchmatrices, 16 p×q intermediate switch matrices and 32 r×s output switchmatrices, wherein the plurality of u×v input switch matrices and theplurality of r×s output switch matrices are 8×8 switch matrices, and theplurality of p×q intermediate switch matrices are 8×16 switch matrices.

In some cases, the RF router of claim 6, wherein when the RF router has128 RF input terminals and 128 RF output terminals, the RF routercomprises 32 u×v input switch matrices, 16 p×q intermediate switchmatrices and 32 r×s output switch matrices, wherein the plurality of u×vinput switch matrices and the plurality of r×s output switch matricesare 8×8 switch matrices, and the plurality of p×q intermediate switchmatrices are 16×16 switch matrices.

The splitters of the RF router may be passive splitters. The combinersof the RF router may be passive combiners.

In some cases, each RF input terminal has an external signal impedanceand the RF router has an internal signal impedance. In such cases, theinput stage further comprises an impedance matching stage coupledbetween each RF input terminal and the corresponding splitter, whereinthe impedance matching stage the external signal impedance to thecorresponding RF input terminal and the internal signal impedance to thecorresponding splitter.

In some cases, at least some r×s output switch matrices comprise anautomatic gain control stage, wherein each automatic gain control stageoperates to adjust the gain of an incoming RF signal.

At least some of the u×v input switch matrix may comprise anequalization stage to equalize the input RF signal.

In some cases, at least some r×s output switch matrices comprise anequalization stage coupled to the automatic gain control stage, whereineach of the equalization stage is configurable to equalize the incomingRF signal.

At least some p×q intermediate switch matrices may comprise anequalization stage for equalizing an incoming RF signal.

The RF router may further comprise a tone insertion module coupled tothe plurality of splitters, wherein the tone insertion module isconfigured to insert a unique tone signal to each of the split inputsignal corresponding to each input RF signal.

The RF router may further comprise a plurality of tone monitoringmodules coupled to at least one u×v input switch matrix, at least onep×q intermediate switch matrix and at least one r×s output switchmatrix, wherein the tone monitoring modules are configured to monitorthe unique tone signal.

In some cases, the RF router may comprise a plurality of connectors forreceiving the plurality of u×v input switch matrices, the plurality ofp×q intermediate switch matrices and the plurality of r×s output switchmatrices, wherein each connector is a self-terminating connectorconfigured to close opposing pins of the connector to provide animpedance in an unconnected mode.

At least one u×v input switch matrix, at least one p×q intermediateswitch matrix and at least one r×s output switch matrix of the RF routermay comprise a sensor configured to detect removal of the u×v inputswitch matrices, p×q intermediate switch matrices and r×s output switchmatrices from the plurality of connectors.

In some cases at least one u×v input switch matrix, at least one p×qintermediate switch matrix and at least one r×s output switch matrixcomprise a sensor configured to detect insertion of the u×v input switchmatrices, p×q intermediate switch matrices and r×s output switchmatrices to the plurality of connectors.

In some cases, at least one u×v input switch matrix, at least one p×qintermediate switch matrix and at least one r×s output switch matrixcomprise a module ejector. In such cases, the sensor is configured todetect whether the module ejector is in an open or close state to detectremoval of the u×v input switch matrices, p×q intermediate switchmatrices and r×s output switch matrices to the plurality of connectors.

The sensor may be a capacitive sensor.

The input RF terminals and the output RF terminals may comprise a BNCconnector.

In some cases, the distances between each splitter and each u×v inputswitch matrix, each u×v input switch matrix and each p×q intermediateswitch matrix, each p×q intermediate switch matrix and each r×s outputswitch matrix, and each r×s output switch matrix and each combiner areequal.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the various embodiments described herein,and to show more clearly how these various embodiments may be carriedinto effect, reference will be made, by way of example, to theaccompanying drawings which show at least one example embodiment, and inwhich:

FIG. 1 illustrates a first example of an RF router 100 with dimensionsof n RF input terminals×m RF output terminals;

FIG. 2 illustrates a second example of an RF router 200 with dimensionsof n RF input terminals×m RF output terminals;

FIG. 3A illustrates a rear view of an example embodiment of a RF router300 with a dimension of 128 RF input terminal×128 RF output terminals;

FIG. 3B illustrates a front view of an example embodiment of a RF router300 with a dimension of 128 RF input terminal×128 RF output terminals;

FIG. 4A illustrates an example RF signal path from an RF input terminal120 to an input of a u×v input switch matrix for a RF router 400;

FIG. 4B illustrates another example of a RF signal path from an RF inputterminal 120 to a u×v input switch matrix for a RF router 400′;

FIG. 4C illustrates another example of a RF signal path from an RF inputterminal 120 to a r×s output switch matrix 465 for a RF router 400″;

FIG. 4D illustrates another example of a RF signal path from a r×soutput switch matrix to a RF output terminal 130 for a RF router 400′″;

FIG. 5 illustrates an example embodiment of a router 500 with adimension of 128 RF input terminals×128 RF output terminals;

FIG. 6 illustrates an example embodiment of a RF router 600 fordemonstrating a built-in redundancy in the router 500 of FIG. 5;

FIG. 7 illustrates an example embodiment of a RF router 700 with adimension of 64 RF input terminals×64 RF output terminals;

FIG. 8 illustrates an example embodiment of a RF router 800 with adimension of 64 RF input terminal×128 RF output terminals;

FIG. 9 illustrates a module ejector assembly of switching matrices;

FIG. 10A illustrates an example embodiment of an input block 1000 of aninput switch matrix; and

FIG. 10B illustrates an example embodiment of an output block 1060 a ofan input switch matrix.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

It will be appreciated that numerous specific details are set forth inorder to provide a thorough understanding of the exemplary embodimentsdescribed herein. However, it will be understood by those of ordinaryskill in the art that the embodiments described herein may be practicedwithout these specific details. In other instances, well-knownprocedures and components have not been described in detail so as not toobscure the embodiments described herein. Furthermore, this descriptionis not to be considered as limiting the scope of the embodimentsdescribed herein in any way, but rather as merely describingimplementation of the various embodiments described herein.

Reference is first made to FIG. 1, which illustrates a first example ofan RF router 100 with dimensions of n RF input terminals×m RF outputterminals. The rear side 110 r of router 100 comprises a plurality of RFinput terminals 120 and a plurality of RF output terminals 130. In a RFrouter 100 with a dimension of n×m, there are ‘n’ RF input terminals 120and ‘m’ RF output terminals 130.

The n RF input terminals are identified at reference numerals 120-1 to120-n. The m first RF output terminals are identified at referencenumerals 130-1 to 130-m. RF Router 100 is configured to connect any ofthe n RF input terminals 120 to any of the m RF output terminals 130. Insome embodiments, the RF router 100 is configured to accommodate 128 RFinput terminals and 128 RF output terminals.

The RF router 100 is configured to connect the n RF input terminals 120to the m RF output terminals 130. The RF router 100 is also configuredto provide redundancy allowing signal paths to be rerouted in the eventof a failure in part of the router 100. For example, in the event of anycomponent failure in an RF signal path, the built-in redundancyfacilitates re-routing of the signal path.

The front side 110 f of router 100 comprises a plurality of switchmatrices. As illustrated, the front side 110 f of the router 100comprises u×v input switch matrices 140, p×q intermediate switchmatrices 160 and r×s output switch matrices 150. Each of the pluralityof switch matrices 140, 150, 160 is a separate unitary element assembledon a card, which includes a printed circuit board. A first u×v inputswitch matrix is illustrated as 140-1 and an i^(th) u×v input switchmatrix is illustrated as 140-i. Similarly, A first r×s output switchmatrix is illustrated as 150-1 and a j^(th) r×s output switch matrix isillustrated as 150-j.

A CLOS switching network provides an advantage of connecting a largenumber of input terminals to a large number of output terminals by usingfewer and small-sized switches than other switching architectures. CLOSswitching networks are a three-stage unidirectional switching network,typically including a number of crossbar switches at each stage. A CLOSnetwork is typically defined in terms of three integers, n, m and r,where r represents a number of switches in the first stage, n representsa number of sources or inputs feeding into each of r switches, and mrepresents a number of outlets for each of the r switches. Accordingly,there are r switches in the first stage, with each switch having ninputs and ‘m’ outputs. The second stage has m switches, each with rinputs and r outputs. The third stage has r switches, each with m inputsand n outputs.

A CLOS network can be a strict-sense non-blocking network when an unusedinput on a switch at the first stage can be routed to an unused outputon a switch at the third stage without having to re-route any existingsignal routes. A sufficient condition for strict-sense non-blocking isthat ‘m’ be greater than or equal to ‘2n−1’. A CLOS network can be arearrangeably non-blocking network when an unused input on a switch atthe first stage is routed to an unused output on a switch at the thirdstage by rearranging existing signal routes. A sufficient condition fora rearrangeably non-blocking CLOS network is that ‘m’ be greater than orequal to ‘n’.

Reference is first made to FIG. 2, which illustrates a second example ofan RF router 200 with dimensions of n RF input terminals×m RF outputterminals. RF router 200 has a modular structure and is assembled in aframe or chassis 210. For example, the RF router 200 may be assembled ina rack mounted chassis. In some embodiments, the router 100 may have anon-modular structure.

In some embodiments, the RF router 200 may be assembled in a singlechassis. For example, the RF router 200 may be configured to accommodate128 input RF signals and 128 output RF signals in a single chassis. Insome other embodiments, the RF router 200 may be assembled over multiplechassis cascaded together. For example, the RF router 200 may beconfigured to accommodate large format RF routers, such as, a 1024×1024RF router over multiple chassis cascaded together.

The router 200 comprises a backplane 220. The backplane 220 comprises aplurality of connectors coupled to the backplane 220 for receiving theplurality of switch matrices. The plurality of u×v input switch matrices240 are received by a plurality of input switch connectors, theplurality of p×q intermediate switch matrices 260 are received by aplurality of intermediate switch connectors and the plurality of r×soutput switch matrices 250 are received by a plurality of output switchconnectors. Each of the switch matrices 240, 250, 260 can be inserted orremoved from the connectors independently. The backplane 220 provideselectrical interconnections between the plurality of switch matrices, aswell as to the plurality of RF input terminals, such as the RF inputterminals 120 and the plurality of RF output terminals, such as the RFoutput terminals 130.

The router 200 also comprises a controller 230 installed within thechassis 210. In other embodiments, controller 230 may be provided as anindependent device and may be coupled to the various switch matricesexternally. For example, the controller 230 may be mounted in a separaterack mounted chassis and may be combined with other device in thatchassis.

Controller 230 may be distributed or may be a part of a larger controlsystem for a communication and signal processing system. Controller 230may control RF router 200 and other devices in the communication systemand will be coupled to such devices, typically through a control datanetwork. Typically, the controller will control RF router 200 and suchother devices in response to requests or control instructions receivedfrom other devices or from a user of the RF router 200 or thecommunication system.

In various embodiments, the connectors attached to the backplane 220 forreceiving the plurality of switch matrices or cards comprising theswitch matrices are self-terminating connectors. Self-terminatingconnectors are configured to close two or more pins of the connector inthe absence of any switch matrices or cards comprising the switchmatrices. For instance, a self-terminating connector may be configuredto close opposing pins of the connector. Two or more pins of theconnector may be closed by, for example, touching the two or more pinstogether.

A self-terminating connector may also be configured to close theopposing pins as soon as a switch matrix or a card comprising the switchmatrix is removed from the connector. For example, in router 200,removal of a switch matrix or a card comprising the switch matrix fromthe connector may be detected and the state of the connector may bechanged from open to close based on such detection.

The self-terminating connector provides terminal impedance in the signalpath of the router 200 when the pins on the connector close. Theterminal impedance may be any impedance equal to the internal signalimpedance for impedance matching in the signal path. For example, theself-terminating connector may provide terminal impedance of 50 ohms, 75ohms or any other suitable impedance equal to the internal signalimpedance to maintain impedance matching within the router 200,depending on the cables and devices used in or with the router. Thishelps to reduce impact on other signals or signal paths upon removal ofone or more switch matrices from one or more connectors.

Reference is next made to FIGS. 3A and 3B, illustrating an exampleembodiment of a RF router 300 with a dimension of 128 RF inputterminal×128 RF output terminals. FIG. 3A illustrates a rear view 310 rof the router 300. Router 300 comprises 128 RF input terminals 320 and128 RF output terminals 330. The RF input and output terminals may beany type or any combination of types of connectors. For example, theseterminals may be 50 ohms BNC connectors, 75 ohms BNC connectors, SMA,Type F, Type N or other types of signal connector.

FIG. 3B illustrates a front view 310 f of the router 300. In the exampleembodiment of router 300 with a dimension of 128 RF input terminals and128 RF output terminals, router 300 comprises 32 u×v input switchmatrices 340, 32 r×s output switch matrices 350 and 16 p×q intermediateswitch matrices 360. Each of the u×v input switch matrices are 8×8switch matrices, configured to connect up to 8 inputs to any one of the8 outputs. Each of the r×s output switch matrices are also 8×8 switchmatrices and each of the p×q intermediate switch matrices are 16×16switch matrices. The arrangement of various switch matrices in therouter 300 are by way of an example only and are not to be construed aslimiting in any way.

Reference is next made to FIGS. 4A-4D, illustrating example embodimentsof input signal paths within a RF router. FIG. 4A illustrates an exampleRF signal path from an RF input terminal 120 to an input of a u×v inputswitch matrix for a RF router 400. The general signal path comprises asplitter 410.

In the illustrated embodiment, the splitter 410 is a 1×2 passivesplitter, which comprises an incoming port 402 coupled to the RF inputterminal 120 and two outgoing ports 404 and 406 coupled to the inputswitch matrices (not shown). The incoming port 402 receives an input RFsignal and the outgoing ports 404, 406 provide the input RF signal attwo locations. The splitter 410 is a passive splitter and is configuredto split the input RF signal without any signal processing, such as,signal amplification.

FIG. 4B illustrates another example of a RF signal path from an RF inputterminal 120 to a u×v input switch matrix for a RF router 400′. In thisembodiment, each signal path comprises an impedance matching stage 430and a splitting stage 410′. The splitting stage 410′ may be similar tothe splitter 410 of FIG. 4A.

In router 400, RF input terminals 120 have external signal impedanceselected to be compatible with the device or devices that produce the RFinput signals. For example, RF input terminals 120 may be coaxial cableterminals and the external signal impedance may be seventy-five ohms, asis typical in many coaxial cable communication systems. In otherembodiments, the external signal impedance may be any other impedancesuitable for coupling to devices that produce the input RF signals.

Router 400 also has internal signal impedance. The internal signalimpedance may be selected based on the impedance characteristics of theterminals of the switch matrices, such as switch matrices 140, 150, 160or any other characteristics of the router 400. For example, if theoutput terminals of the p×q intermediate switch matrices 160 have animpedance of fifty ohms, the internal signal impedance may be selectedto be fifty ohms.

As illustrated, an input RF signal 405 is received at a corresponding RFinput terminal 120. The RF input terminal 120 is coupled to an impedancematching stage 430. Impedance matching stage 430 provides an inputimpedance that matches the external signal impedance of router 400 andan output impedance that matches the internal signal impedance of therouter 400.

In some embodiments, the external signal impedance and the internalsignal impedance of the router 400 are equal. In such cases, noimpedance matching may be required and the impedance matching stage 430may be an optional stage.

FIG. 4C illustrates another example of a RF signal path from an RF inputterminal 120 to a r×s output switch matrix 465 for a RF router 400″.Router 400″ comprises a splitting stage 410″, similar to the splitter410. Router 400″ also comprises various equalization stages 440, 450,460 along the signal path. For example, router 400″ may compriseequalization stage 440 in some or all of the u×v input switch matrices445, equalization stage 450 in some or all of p×q intermediate switchmatrices 455 and equalization stage 460 in some or all of r×s outputswitch matrices 465. The equalization stages 440, 450, 460 receive an RFsignal and processes it to provide an equalized signal. For example, theequalization stage comprises an attenuator with positive slope. Theattenuator attenuates the RF signal to avoid increasing the noise withinthe router 400″. In some embodiments, the equalization stages 440, 450,460 are configurable, such as, for example, the attenuation levels arecustomizable. In some other embodiments, the equalization stages 440,450, 460 are not configurable.

Reference is next made to FIG. 4D illustrating another example of a RFsignal path from a r×s output switch matrix to a RF output terminal 130for a RF router 400′″. Router 400′″ comprises an automatic gain controlstage 470 to adjust the gain of incoming RF signals. Router 400′″maintains a sufficiently high RF signal gain level thought out therouter so that the RF signals are not degraded by some or all of thesplitters, trace losses, equalization stages, power monitoring, tonemonitoring or switch matrices etc.

Router 400′″ comprises the automatic gain control stage 470 in some orall of the r×s output switch matrices 465′. The gain of the RF signalsmay be adjusted at the r×s output switch matrices 465′ to maintain highoutput levels and to limit the signal noise. In various embodiments, theautomatic gain control stage 470 at the r×s output switch matrices 465′are configurable, such as, for example, the gain is customizable. Forexample, different r×s output switch matrices 465′ may be controlled toprovide a different gain at the corresponding gain control stages. Insome other embodiments, router 400′″ may comprise one or more automaticgain control stage 470 in other locations along the signal path.

Router 400′″ also comprises a combiner 480. In the illustratedembodiment, combiner 480 is a 2×1 passive combiner, which comprises twoincoming ports 485, 490 coupled to the r×s output switch matrices, suchas the r×s output switch matrix 485′ and another r×s output switchmatrix, and one outgoing port 495 coupled to the RF output terminal 130.The two incoming ports 485, 490 receive RF signals from two r×s outputswitch matrices and the one outgoing port 495 provides a combined RFsignal. The combiner RF signal is the output RF signal seen at the RFoutput terminal 130.

Reference is next made to FIG. 5, illustrating an example embodiment ofa router 500 with a dimension of 128 RF input terminals×128 RF outputterminals. Router 500 comprises an input stage 580 and an output stage590. The input stage 580 comprises 128 RF input terminals, such as RFinput terminals 120. For example, router 500 comprises a first RF inputterminal 502, a second RF input terminal 504 and so on. RF router 500can receive up to 128 input RF signals, where each RF input terminal isconfigured to receive an input RF signal.

The input stage 580 also comprises a plurality of u×v input switchmatrices 520 and a plurality of splitters 510. Each splitter 510 isconnected to each RF input terminal for coupling a corresponding inputRF signal to at least one u×v input switch matrix 520. Each splitter 510receives an input RF signal and provides a corresponding RF signal attwo locations. For example, router 500 comprises a first splitter 510-athat receives an input RF signal from RF input terminal 502 and providescorresponding RF signals at two outgoing ports 506, 508 of the splitter510-a. Similarly, router 500 comprises a second splitter 510-b thatreceives an input RF signal from RF input terminal 504 and providescorresponding RF signals at two outgoing ports 512, 514 of the splitter510-b. In other embodiments, splitter 510 may be configured to receivean input RF signal and provide it at more than one location.

Each u×v input switch matrix 520 of router 500 is connected to usplitters 510. In router 500, each u×v input switch matrix 520 is a 8×8switch matrix and is configured to receive up to 8 inputs. Each 8×8input switch matrix 520 is connected to 8 different splitters 510 at oneof the two outgoing ports. For example, in router 500, a first 8×8 inputswitch matrix 520-a is connected to outgoing port 506 of the firstsplitter 510-a at one of the 8 inputs. The first 8×8 input switch matrix520-a is also connected to outgoing port 512 of the second splitter510-b at another of the 8 inputs.

Similarly, a second 8×8 input switch matrix 520-b is connected to theother outgoing port 508 of the first splitter 510-a at one of the 8inputs and connected to the other outgoing port 514 of the secondsplitter 510-b at another of the 8 inputs. In router 500, each of theu×v input switch matrix 520 has each of its u inputs connected toexactly one of the plurality of splitters 510 at exactly one of the twooutgoing ports.

Router 500 further comprises a plurality of p×q intermediate switchmatrices 530 coupled between the plurality of u×v input switch matrices520 and a plurality of r×s output switch matrices 540. In router 500,each of the p×q intermediate switch matrices 530 are 16×16 switchmatrices configured to connect up to 16 inputs to 16 outputs.

Each of the p×q intermediate switch matrices 530 has its inputs coupledto outputs of the u×v input switch matrices 520 such that each of the pinputs of each p×q intermediate switch 530 is connected to exactly oneoutput of the plurality of u×v input switch matrices 520. In router 500,each of the p inputs of each p×q intermediate switch matrices 530 areconnected to outputs of different u×v input switch matrices 520.

For example, router 500 comprises a first intermediate switch matrix530-a, with 16 inputs and 16 outputs. Each of the 16 inputs of the firstintermediate switch matrix 530-a is connected to exactly one output ofthe u×v input switch matrices 520, and the exactly one outputcorresponds to a different u×v input switch matrix 520, such as output506′ of the first input switch matrix 520-a.

As illustrated, each of the 8 outputs of the first input switch matrix520-a is connected to a different p×q intermediate switch matrix 530.For example, output 506′ of the first input matrix 520-a is connected tothe first intermediate switch matrix 530-a and the output 512′ of thefirst input matrix 520-a is connected to a second intermediate switchmatrix 530-b. Similarly, output 514′ of the second input switch matrix520-b is connected to a different intermediate switch matrix 530-p. Theinterconnections of various switch matrices are illustrated in moredetail in FIG. 6.

The output stage 590 of router 500 comprises a plurality of r×s outputswitch matrices 540 and a plurality of combiners 550. In router 500,inputs of each r×s output switch matrices 540 are connected to outputsof the p×q intermediate switch matrices 530 such that each input of eachr×s output switch matrix 540 is coupled to exactly one output of theplurality of p×q intermediate switch matrices 530. Furthermore, inputsof each r×s output switch matrix 540 are connected to a different p×qintermediate switch matrix 530.

In router 500, each of the r×s output switch matrix 540 is a 8×8 switchmatrix having 8 inputs and 8 outputs. Each one of the 8 inputs of eachoutput switch matrix 540 is connected to a different 16×16 intermediateswitch matrix 530. For example, a first output switch matrix 540-a hasone of the 8 inputs connected to output 506″ of the first intermediateswitch matrix 530-a and another of the 8 inputs connected to output 512″of the second intermediate switch matrix 530-b.

Combiners 550 are coupled between the plurality of r×s output switchmatrices 540 and a plurality of RF output terminals, such as RF outputterminals 130. In router 500, each combiner 550 is connected to exactlyone output of two different r×s output switch matrices 540. In someother embodiments, each combiner may be connected to more than twooutputs of different r×s output switch matrices.

For example, a first combiner 550-a is connected to output 506′″ of thefirst 8×8 output switch matrix 540-a and output 508′″ of a second 8×8output switch matrix 540-b. Similarly, a second combiner 550-b isconnected to output 512′″ of the first 8×8 output switch matrix 540-aand output 514′″ of the second 8×8 output switch matrix 540-b.

In router 500, each combiner 550 receives RF signals at the two incomingports and combines two different signals into one outgoing port. Theoutgoing port of each combiner 550 is connected to an RF outputterminal. For example, the outgoing port of the first combiner 550-a isconnected to RF output terminal 552 and the outgoing port of the secondcombiner 550-b is connected to RF output terminal 554. In some otherembodiments, the combiners 550 may be coupled with impedance matchingstages before connecting to the RF output terminals.

RF router 500 comprises 32 u×v input switch matrices 520, where eachinput switch matrix 520 is a 8×8 switch circuit. Router 500 comprises 16p×q intermediate switch matrices 530, where each intermediate switchmatrix 530 is a 16×16 switch circuit. Router 500 further comprises 32r×s output switch matrices 540.

Router 500 further comprises a tone injection module 560 and a tonemonitoring module 570. Tone injection module 560 is configured to add orinsert tones to the RF signals. In some examples, the tone injectionmodule 560 inserts audio tones to the RF signals. In some otherexamples, the tones may be inaudible but detectable by the tonemonitoring module 570. In some further examples, the tones may be out ofband with the RF signals so that the tones do not affect the signals.

The tones may be inserted when the RF signals are received by u×v inputswitch matrices 520. For example, the tone may be inserted when the RFsignal reaches a first amplifier within the u×v input switch matrix 520.

Router 500 further comprises a tone monitoring module 570 configured tomonitor injected tones at various stages along the signal path. The tonemonitoring module 570 facilitates tone monitoring to determine acomponent failure along the signal path, such as, for example, an inputswitch matrix failure, an intermediate switch matrix failure etc.

The tone monitoring module 570 may also be configured to monitor powercorresponding to input RF signals. For example, the tone monitoringmodule 570 may measure an incoming signal power at a first input switchmatrix and at a second input switch matrix, where the second switchmatrix is configured to receive the same inputs as the first inputswitch matrix. The measured signal powers may be compared to detectfaulty input switch matrix.

The tone monitoring module 570 is also configured to monitor tones atthe input of p×q intermediate switch matrices 530 and at the input ofr×s output switch matrices 540 prior to any other processing. Forexample, the tone is monitored when the incoming RF signal reaches afirst amplifier within a p×q intermediate switch matrix 530. Similarly,the tone is monitored when the incoming RF signal reaches a firstamplifier within a r×s output switch matrix 540.

In some embodiments, the r×s output switch matrices monitor one another.For example, a r×s output switch matrix, which may or may not be drivinga RF signal, can monitor what the other r×s output switch matrix coupledto the same RF output terminal is driving. This facilitates faultdetection with r×s output switch matrices.

The r×s output switch matrices may also be configured to remove the toneinserted by the tone injection module 560 so that the correspondingoutput RF signal does not comprise the tone. Accordingly, the output RFsignal reaching the downstream device or user is not affected by thetones.

At least one of the plurality of u×v input switch matrices 520, p×qintermediate switch matrices 530 and r×s output switch matrices 540 inrouter 500 are redundant switch circuits. Redundancy is discussed infurther detail below with reference to FIG. 6.

Reference is next made to FIG. 6 illustrating an example embodiment of aRF router 600. Router 600 is a sub-set of router 500 of FIG. 5 forillustrating a built-in redundancy in the router 500. RF router 600comprises eight RF input terminals, eight splitters 610, a first u×vinput switch matrix 620, a second u×v input switch matrix 625, 16 p×qintermediate switch matrices 630, a first r×s output switch matrix 640,a second r×s output switch matrix 645, and 8 combiners 650.

The interconnection of various components is illustrated by use of samealpha-numeric labels. For example, each splitter 610 is connected to oneRF input terminal A-H. Each splitter 610 has two outgoing ports, such asa splitter connected to RF input terminal A has two outgoing ports A₁and A₂. Each input of the first u×v input switch matrix 620 is connectedto a first of the two outgoing ports of each of the eight splitters 610.Each input of the second u×v input switch matrix 625 is connected to asecond of the two outgoing ports of each of the eight splitters 610.Accordingly, both the first input switch matrix 620 and the second inputswitch matrix 625 receive signals corresponding to the same input RFsignal. This creates redundancy in the router 600 since even if one ofthe input switch matrices 620, 625 undergoes failure, the RF signal pathis not lost.

Similarly, the plurality of p×q intermediate switch matrices 630 and theplurality of r×s output switch matrices, such as 8×8 output switchmatrices 640, 645 can provide redundant signal paths in router 600. Asillustrated, each output of the first u×v input switch matrix 620 isconnected to a different p×q intermediate switch matrix 630. Asillustrated, output A₁ of the first input switch matrix 620 is connectedto one input of a first p×q intermediate matrix 630-1. Output B₁ of thefirst input switch matrix 620 is connected to one input of a second p×qintermediate matrix 630-2 and output C₁ of the first input switch matrix620 is connected to one input of a third p×q intermediate matrix 630-3.

In an event of component failure, such as failure of any 16×16intermediate switch matrices 630, router 600 re-routes signal pathsthrough other 16×16 intermediate switch matrices 630. The re-routing isbased on switch matrix availability.

For example, in router 600, both the first p×q intermediate matrix 630-1and the ninth p×q intermediate matrix 630-9 are configured to receivethe same set of RF signals at the ‘p’ inputs. Accordingly, in the eventof a failure of any one of p×q intermediate switch matrices 630, such asthe first p×q intermediate matrix 630-1, the RF router 600 can re-routethe RF signal through another corresponding p×q intermediate switchmatrices 630, such as the ninth p×q intermediate matrix 630-9 so that noRF signal is lost due to component failure.

Similarly, router 600 may connect output H₂ of the second input switchmatrix 625 to one input of a sixteenth p×q intermediate switch matrix630-16 in the event of failure of the eighth p×q intermediate switchmatrix 630-8. Accordingly, in the event of component failure, at leastone other p×q intermediate switch matrix 630 may be configured toreceive the same set of RF signals at each of the p inputs as the failedp×q intermediate switch matrix 630, thereby creating a redundancy.

Similarly, in an event of component failure, such as failure of any 8×8output switch matrices 640,645, router 600 re-routes signal pathsthrough other 8×8 output switch matrices 640,645. As illustrated, boththe first r×s output switch matrix 640 and the second r×s output switchmatrix 645 are configured to receive the same set of RF signals at the rinputs. In the event of failure of 8×8 output switch matrix 640, router600 may re-route signals through the 8×8 output switch matrix 645,thereby preventing any signal loss.

In various embodiments, the tone monitoring module 570 monitors anyfailure in the RF signal path within the router. Upon failure detection,a controller automatically re-routes a signal path within the router toprevent the loss of RF signals.

In some embodiments, router 600 comprises two controllers coupled to thevarious components of the router. The various switching matrices monitorhow frequently they are polled by each controller. In the event that aswitching matrix does not get polled by a controller within certainduration of time, the switching matrix informs the other controller thatthere may be a fault with the timed out controller. The duration of timefor timeout may be a fixed pre-determined duration of time or achangeable duration of time. This may facilitate fault detection in thecontrollers within the router. Use of two controllers also providescontroller redundancy within the router. Failure detection of onecontroller may trigger the router to switch to the functional controllerwhile disregarding the timed out controller.

Reference is next made to FIG. 7 illustrating an example embodiment of aRF router 700 with a dimension of 64 RF input terminals×64 RF outputterminals. Router 700 is configured to provide an architecture thatfacilitates internal RF signal re-routing.

RF router 700 comprises 64 RF input terminals and 64 splitters 710 witheach RF input terminal connected to a connector. RF router 700 furthercomprises 16 u×v input switch matrices 720, 16 p×q intermediate switchmatrices 730, and 16 r×s output switch matrices 740. Each of the 64splitters 710 comprises a 1×2 splitting circuit. Each u×v input switchmatrix 720, each p×q intermediate switch matrix 730 and each r×s outputswitch matrix 740 comprises a 8×8 switching circuit.

RF router 700 further comprises 64 combiners 750 and 64 RF outputterminals with each combiner 750 connected to a RF output terminal. Inrouter 700, each combiner 750 comprises a 2×1 combiner circuit.

As illustrated, each of the outgoing port of each splitter 710 isconnected to different u×v input switch matrices 720 at exactly oneinput. Each output of each u×v input switch matrix 720 is connected todifferent p×q intermediate switch matrices 730 at exactly one input.

The plurality of r×s output switch matrices 740 mirror the architectureand interconnections of the plurality of u×v input switch matrices 720to the plurality of p×q intermediate switch matrices 730. Accordingly,at least one of the plurality of u×v input switch matrices 720, p×qintermediate switch matrices 730 and r×s output switch matrices 740provide redundancy in the router 700 to facilitate re-routing of RFsignals, for example, in the event of component failure.

Reference is next made to FIG. 8 illustrating an example embodiment of aRF router 800 with a dimension of 64 RF input terminal×128 RF outputterminals. RF router 800 is configured to provide an architecture thatfacilitates internal RF signal re-routing.

RF router 800 comprises 64 RF input terminals and 64 splitters 810 whereeach splitter 810 is connected to RF input terminal. Each of the 64splitters 810 comprises a 1×2 splitting circuit.

RF router 800 further comprises 16 u×v input switch matrices 820, 16 p×qintermediate switch matrices 830 and 32 r×s output switch matrices 840.Each u×v input switch matrix 820 comprises a 8×8 switching circuit. Eachp×q intermediate switch matrix 830 comprises a 8×16 switching circuitand each r×s output switch matrix 840 comprises a 8×8 switching circuit.

RF router 800 further comprises 128 combiners 850 and 128 RF outputterminals where each combiner 850 is connected to a RF output terminal.In router 800, each RF combiner 850 comprises a 2×1 combiner circuit.

In some other embodiments, the RF router may have a dimension of 1024 RFinput terminals×1024 RF output terminals. In this embodiment, the RFrouter comprises an input stage, a middle stage and an output stage. Theinput stage comprises 1024 splitters and 16 u×v input switch matrices.The splitters comprise a 1×2 splitting circuit. The splitters may bepassive or active splitters. For example, the splitters may be Wilkinsonsplitters. Each of the u×v input switch matrix comprises a 128×128switching circuit.

The middle stage comprises 256 p×q intermediate switch matrices. Each ofthe p×q intermediate switch matrix comprises a 8×8 switching circuit.The output stage comprises 16 r×s output switch matrices. Each of ther×s output switch matrices comprises a 128×128 switching circuit. Theoutput stage further comprises 1024 combiners configured to combine twosignals into one. The combiners may be passive or active combiners. Forexample, the combiners may be Wilkinson combiners.

The RF router in this embodiment may be assembled over multiple chassiscascaded together. For example, the input stage, the middle stage andthe output stage may be in three different chassis.

Reference is next made to FIG. 9, illustrating a module ejector assemblyof switching matrices. In this embodiment, a 8×8 switch matrix, such asa u×v input switch matrix 140 of FIG. 1, is assembled on a card 910 anda 16×16 switch matrix, such as p×q intermediate switch matrix 160 ofFIG. 1, is assembled on a card 920. Each card 910, 920 comprises aprinted circuit board containing the switching circuitry.

As illustrated, card 910 comprises a module ejector 930. The card 910comprises a connecting side 960 configured to be received by a connectormounted on the router. The module ejector 930 is connected to the card910 on a side opposite to the connecting side 960. In other embodiments,the module ejector 930 may be connected to the card 910 on any otherside, other than the connecting side 960.

The card 920 comprises two module ejectors, a first module ejector 940and a second module ejector 950. The connecting side 970 of the card 920is received by a connector mounted on the router. The first moduleejector 940 and the second module ejector 950 are illustrated on theopposite side of the card 920 than the connecting side 970. In otherembodiments, the first module ejector 940 and the second module ejector950 may be connected elsewhere on the card 920. The module ejectors 930,940, 950 are rotatable around a fixed axis.

Card 910 comprises a sensor 980 to detect the removal of the card 910from a connector mounted on the router. Similarly, card 920 comprises asensor 990. Cards 910, 920 may comprise more than one sensors to detectcard removal from connectors. For example, card 920 may comprise anothersensor close to the first module ejector 940. In the illustratedembodiments, the sensors 980, 990 are capacitive sensors comprisingcapacitive traces.

When card 910 is connected to the router at the connecting side 960, themodule ejector 930 is in a closed position. In this position, the moduleejector 930 overlies the sensor 980, either in part or entirely.

Similarly, when card 920 is connected to the router at the connectingside 970, both the first module ejector 940 and the second moduleejector 950 are in a closed position. In this position, the moduleejector 950 overlies the sensor 990, either in part or entirely. Inthose embodiments where the card 920 comprises more than one sensor, allthe corresponding module ejectors overlie the sensors either in part orentirety in the closed position.

The sensors 980, 990 detect the proximity of approaching objects, suchas, for example, a finger of a router operator, just before theapproaching object establishes a contact with the cards 910, 920 or themodule ejectors 930, 940, 950. For example, when the sensors 980, 990are capacitive sensors, the proximity of approaching objects or thecontact by approaching objects is detected by detecting a change in thecapacitance in the sensors 980, 990.

This detection facilitates re-routing of signal paths within the routersuch that no signal is lost when the cards 910, 920 are removed ordisconnected from the router.

In various embodiments, this detection of upcoming or actual cardremoval also triggers a controller to close pins of the self-terminatingconnector corresponding to the card. The self-terminating connectorintroduces terminal impedance equal to the internal signal impedance forimpedance matching in the signal path and prevents impact on othersignals.

In one embodiment, a tone monitoring module, such as module 570, detectswhether any switch matrix along a signal path has failed, such as, forexample, failure of any input switch matrices 520, any intermediateswitch matrices 530 etc. A failed or defective card or input matrix isreplaced with a new card to restore redundancy in the router.

Replacing a bad or faulty card in a signal path in the router may causerouter and signal disturbances. However, the router in the exampleembodiments disclosed herein comprise cards configured to provide hotswappable and hot pluggable capabilities. Hot swappable and hotpluggable cards may be removed and replaced without significantlyinterrupting the router.

Reference is again made to FIG. 5 illustrating an example embodiment ofa router 500. The backplane of router 500 is configured to match lengthsof RF signal paths within the router. In the backplane of router 500,the lengths of each of the traces from splitters 510 to u×v input switchmatrices 520 are equal. Similarly, the lengths of each of the tracesfrom u×v input switch matrices 520 to p×q intermediate switch matrices530 are equal. The backplane of router 500 further comprises equaltraces from the p×q intermediate switch matrices 530 to r×s outputswitch matrices 540 and from r×s output switch matrices 540 to combiners550.

Reference is next made to FIG. 10A, illustrating an example embodimentof an input block 1000 of an input switch matrix, such as a u×v inputswitch matrix 520-a, which is a 8×8 switch matrix. The input block 1000illustrates the switching circuitry corresponding to only one of the 8input terminals of the input switch matrix 520-a. The input block 1000comprises an input terminal 1010 a for receiving an input RF signal andswitches it to one or more of the 8 output blocks 1060 a-1060 h. Anexample embodiment of an output block is illustrated in FIG. 10B.

Coupled to each output block 1060 a-1060 h is a 2×1 switch 1040 a-1040h. For example, coupled to output block 1060 a is a 2×1 switch 1040 a.The 2x1 switch is configured to connect an input RF signal received atthe input terminal 1010 a to the corresponding output block 1060 a in onstage and to ground in off stage. The switch may connect the input RFsignal to ground in off stage via a resistor. A router controller isconfigured to turn the switch on or off to facilitate signal routingwithin the router.

As illustrated, in the input block 1000, the input RF signal received atthe input terminal 1010 a undergoes some signal processing at signalprocessing module 1020, such as, for example, signal amplification.Trace 1015 connects the input terminal 1010 a to the signal processingmodule 1020. The signal processing module 1020 is connected to each ofthe 2×1 switches 1040 a-1040 h via traces 1030 a-1030 h. For example,the signal processing module 1020 connects to the switch 1040 a viatrace 1030 a.

In the input switch matrix 1000, each of the switches 1040 a-1040 h areconnected to the output blocks 1060 a-1060 h via traces 1050 a-1050 h.For example, switch 1040 a is connected to the output block 1060 a viatrace 1050 a.

In the various example embodiments of routers disclosed herein, eachinput switch matrix 1000 is configured to match trace lengths within thesignal path. All traces 1050 a-1050 h connecting switches 1040 a-1040 hto output blocks 1060 a-1060 h are equal, illustrated as trace 1050.

Although only one of the 8 input terminals of the input switch matrix isillustrated by input block 1000, the input switch matrix is configuredto have trace length matching across all of the 8 inputs.

The input switch matrix is configured to have an equal trace length ofsum of traces 1015 and 1050 across all 8 inputs, i.e. the sum of tracelengths between an input terminal of the input switch matrix, such asthe input terminal 1010 a and the corresponding input processing module,such as the input processing module 1020, as well as between theswitches, such as switches 1040 a-1040 h and the output terminals, suchas the output terminal 1050 a-1050 h (trace 1050) are equal across allof the 8 inputs. Trace 1030 a connecting the signal processing module1020 to a first switch 1040 a is equal across all inputs. Similarly,traces 1030 b-1030 h are equal across all inputs.

Reference is next made to FIG. 10B, illustrating an example embodimentof an output block 1060 a of the u×v input switch matrix 520-a. Theoutput block 1060 a illustrates the switching circuitry corresponding toonly one of the 8 output terminals of the input switch matrix 520-a. Theoutput block 1060 a comprises an output terminal 1140 a for providing aRF signal corresponding to the input RF signal received at the inputterminals of the input switch matrix.

The output block 1060 a further comprises an 8×1 switch 1100, an outputprocessing module 1120 and a trace 1130 connecting the output processingmodule 1120 to the output terminal 1140 a. The 8×1 switch 1100 isconnected to 8 2×1 switches from different input blocks of the u×v inputswitch matrix 520-a. For example, the 8×1 switch 1100 is connected toswitch 1040 a via trace 1050 a. Other input blocks are configured toconnect one of the 8 switches connected to the output block 1060 a viatraces 1102 a-1102 g.

In the various embodiments enclosed herein, a router is configured tomatch trace lengths across various signal paths within the input block1000 and output block 1060 a of the u×v input switch matrix 520-a.

The u×v input switch matrix 520-a is configured to have the sum of tracelengths corresponding to traces 1030 a and 1130 equal along all inputand output blocks. For example, the u×v input switch matrix 520-a isconfigured to have the sum of trace 1030 b and trace length connectingan output processing module and an output terminal of output block 1060b equal to sum of traces 1030 a and 1130. Similarly, sum of tracelengths 1030 c and trace corresponding to trace 1130 in output block1060 c, sum of trace lengths 1030 d and trace corresponding to trace1130 in output block 1060 d, sum of trace lengths 1030 e and tracecorresponding to trace 1130 in output block 1060 e, sum of trace lengths1030 f and trace corresponding to trace 1130 in output block 1060 f, sumof trace lengths 1030 g and trace corresponding to trace 1130 in outputblock 1060 g, sum of trace lengths 1030 h and trace corresponding totrace 1130 in output block 1060 h are all equal to each other and equalto sum of traces 1030 a and 1130.

In various embodiments, the various routers disclosed herein provideredundancy with respect to other components within the router. Forexample, some routers disclosed herein provide low-noise block (LNB)power insertion and power supply redundancy. Such routers may comprisetwo or more LNB power inserters within the router chassis such that eachLNB power inserter can provide power to all u×v input switch matrices.Similarly, such routers may comprise extra power supplies. For example,such routers may comprise three power supplies where only two arerequired for the router to function. Such routers may also compriseextra cooling capabilities, such as, for example, by using an extra fan.Extra cooling capabilities may also be provided by switching functionalfans from a low cooling setting to a high cooling setting when one ormore fans undergo failure. For example, a router chassis may comprisefour fans for normal router functionality. The four fans may beconfigured to run at a low setting until one of the fans fail. Inresponse, the remaining functional fans may then be configured to run ata high setting.

The present invention has been described here by way of example only,while numerous specific details are set forth herein in order to providea thorough understanding of the exemplary embodiments described herein.However, it will be understood by those of ordinary skill in the artthat these embodiments may, in some cases, be practiced without thesespecific details. In other instances, well known methods, procedures andcomponents have not been described in detail so as not to obscure thedescription of the embodiments. Various modification and variations maybe made to these exemplary embodiments without departing from the spiritand scope of the invention, which is limited only by the appendedclaims.

We claim:
 1. A RF router comprising: (a) a controller; (b) an inputstage comprising a plurality of RF input terminals, wherein each RFinput terminal is configured to receive an input RF signal, and whereineach input stage further comprises: a plurality of u×v input switchmatrices; and a splitter connected to each RF input terminal forcoupling a corresponding input RF signal to at least one u×v inputswitch matrix; (c) a plurality of p×q intermediate switch matrices,wherein inputs of each p×q intermediate switch matrices are coupled tooutputs of the u×v input switch matrices such that each input of eachp×q intermediate switch matrix is coupled to exactly one output of theplurality of u×v input switch matrices; (d) an output stage comprising:a plurality of r×s output switch matrices, wherein inputs of each r×soutput switch matrix are coupled to outputs of the p×q intermediateswitch matrices such that each input of each r×s output switch matrix iscoupled to exactly one output of the plurality of p×q intermediateswitch matrices; and a combiner coupled between the plurality of r×soutput switch matrices and a plurality of RF output terminals, whereineach RF output terminal is configured to provide an output RF signal;and wherein at least one of the plurality of u×v input switch matrices,the plurality of p×q intermediate switch matrices and the plurality ofr×s output switch matrices are redundant.
 2. The RF router of claim 1,wherein the inputs of each p×q intermediate switch matrix are coupled todifferent u×v input switch matrices.
 3. The RF router of claim 1,wherein the inputs of each r×s output switch matrix are coupled todifferent p×q intermediate switch matrices.
 4. The RF router of claim 1,wherein the splitter is configured to couple the corresponding input RFsignal to different u×v input switch matrices.
 5. The RF router of claim1, wherein the combiner is configured to couple different r×s outputswitch matrices to a RF output terminal.
 6. The RF router of claim 1,wherein the RF router has at least 64 RF input terminals.
 7. The RFrouter of claim 6, wherein the RF router has at least 64 RF outputterminals.
 8. The RF router of claim 7, wherein when the RF router has64 RF input terminals and 64 RF output terminals, the RF routercomprises 16 u×v input switch matrices, 16 p×q intermediate switchmatrices and 16 r×s output switch matrices, wherein the plurality of u×vinput switch matrices, the plurality of p×q intermediate switch matricesand the plurality of r×s output switch matrices are 8×8 switch matrices.9. The RF router of claim 7, wherein when the RF router has 64 RF inputterminal and 128 RF output terminals, the RF router comprises 16 u×vinput switch matrices, 16 p×q intermediate switch matrices and 32 r×soutput switch matrices, wherein the plurality of u×v input switchmatrices and the plurality of r×s output switch matrices are 8×8 switchmatrices, and the plurality of p×q intermediate switch matrices are 8×16switch matrices.
 10. The RF router of claim 6, wherein when the RFrouter has 128 RF input terminals and 128 RF output terminals, the RFrouter comprises 32 u×v input switch matrices, 16 p×q intermediateswitch matrices and 32 r×s output switch matrices, wherein the pluralityof u×v input switch matrices and the plurality of r×s output switchmatrices are 8×8 switch matrices, and the plurality of p×q intermediateswitch matrices are 16×16 switch matrices.
 11. The RF router of claim 1,wherein the splitter is a passive splitter and the combiner is a passivecombiner.
 12. The RF router of claim 1, wherein each RF input terminalhas an external signal impedance and wherein the RF router has aninternal signal impedance, and wherein the input stage further comprisesan impedance matching stage coupled between each RF input terminal andthe corresponding splitter, wherein the impedance matching stage theexternal signal impedance to the corresponding RF input terminal and theinternal signal impedance to the corresponding splitter.
 13. The RFrouter of claim 1, wherein at least some r×s output switch matricescomprise an automatic gain control stage, wherein each automatic gaincontrol stage operates to adjust the gain of an incoming RF signal. 14.The RF router of claim 1, wherein at least some of the u×v input switchmatrix comprise an equalization stage to equalize the input RF signal.15. The RF router of claim 13, wherein at least some r×s output switchmatrices comprise an equalization stage coupled to the automatic gaincontrol stage, wherein each of the equalization stage is configurable toequalize the incoming RF signal.
 16. The RF router of claim 1, whereinat least some p×q intermediate switch matrices comprise an equalizationstage for equalizing an incoming RF signal.
 17. The RF router of claim1, further comprising a tone insertion module coupled to the pluralityof splitters, wherein the tone insertion module is configured to inserta unique tone signal to each of the split input signal corresponding toeach input RF signal.
 18. The RF router of claim 17, further comprisinga plurality of tone monitoring modules coupled to at least one u×v inputswitch matrix, at least one p×q intermediate switch matrix and at leastone r×s output switch matrix, wherein the tone monitoring modules areconfigured to monitor the unique tone signal.
 19. The RF router of claim1, further comprising a plurality of connectors for receiving theplurality of u×v input switch matrices, the plurality of p×qintermediate switch matrices and the plurality of r×s output switchmatrices, wherein each connector is a self-terminating connectorconfigured to close opposing pins of the connector to provide animpedance in an unconnected mode.
 20. The RF router of claim 1, whereinat least one u×v input switch matrix, at least one p×q intermediateswitch matrix and at least one r×s output switch matrix comprise asensor configured to detect removal of the u×v input switch matrices,p×q intermediate switch matrices and r×s output switch matrices from theplurality of connectors.
 21. The RF router of claim 1, wherein at leastone u×v input switch matrix, at least one p×q intermediate switch matrixand at least one r×s output switch matrix comprise a sensor configuredto detect insertion of the u×v input switch matrices, p×q intermediateswitch matrices and r×s output switch matrices to the plurality ofconnectors.
 22. The RF router of claim 20, wherein at least one u×vinput switch matrix, at least one p×q intermediate switch matrix and atleast one r×s output switch matrix comprise a module ejector and whereinthe sensor is configured to detect whether the module ejector is in anopen or close state to detect removal of the u×v input switch matrices,p×q intermediate switch matrices and r×s output switch matrices to theplurality of connectors.
 23. The RF router of claim 22, wherein thesensor is a capacitive sensor.
 24. The RF router of claim 1, wherein theinput RF terminals and the output RF terminals comprise a BNC connector.25. The RF router of claim 1, wherein distances between each splitterand each u×v input switch matrix, each u×v input switch matrix and eachp×q intermediate switch matrix, each p×q intermediate switch matrix andeach r×s output switch matrix, and each r×s output switch matrix andeach combiner are equal.